System and method for producing a cross-fold in folded sheet material

Abstract

A cross-fold system for use in combination with a device for folding sheet material and includes a rigid guide structure having a stationary reaction surface for supporting and guiding folded sheet material along a feed path between a sheet feed mechanism and a tensioning mechanism. Furthermore, the cross-fold system includes a paper break assembly disposed between the sheet feed mechanism and the tensioning mechanism. The paper break assembly, furthermore, includes an abrasion bar disposed transversely of the feed path and in opposed relation to the rigid guide. Moreover, the paper break assembly is repositionable from an active position to an inactive position such that, in the active position, the abrasion bar pressingly engages the sheet material against the stationary reaction surface of the guide assembly, and, in the inactive position, the abrasion bar permits the sheet material to pass to the tensioning mechanism without engaging the sheet material. When the paper break assembly is in the active position, the tensioning mechanism is operative to pull the folded sheet material across the abrading bar to yield the adhesive bond between the reinforcing fibers of the sheet material. As such, a subsequent cross-fold of the folded sheet material is facilitated.

Description

FIELD OF THE INVENTION [0001]The present invention relates to folding apparatus for producing folded sheet material, and, more particularly, to a new and useful system and method for producing one or more cross-folds in a sheet material which has been previously folded, e.g., about an orthogonal fold line.BACKGROUND OF THE INVENTION [0002]In the context of mailpiece delivery, a “self-mailer” is a term used to define mailpieces which employ some portion of its content information or material to form a finished mailpiece, i.e., a mailpiece ready for delivery. In addition to certain efficiencies gained from the dual use of paper stock, i.e., as both envelope and content material, self-mailers mitigate the potential for disassociation of content material from the mailing envelope, i.e., preventing mail from being delivered to an incorrect address.[0003]One example of a self-mailer includes a sheet of content material which has been folded, e.g., a bi- or tri-fold brochure or pamphlet an...

AI Technical Summary

Benefits of technology

[0009]A cross-fold system is provided for use in combination with a device for folding sheet material. The cross fold system includes a rigid guide structure having a stationary reaction surface for supporting and guiding folded sheet material along a feed path between a sheet feed mechanism and a tensioning mechanism. Furthermore, the cross-fold system includes a paper break assembly disposed between the sheet feed mechanism and the tensioning mechanism. The paper break assembly, furthermore, includes an abrasion bar disposed transversely of the feed path and in opposed relation to the rigid guide. Moreover, the paper break assembly is repositionable from an active position to an inactive position such that, in the active position, the abrasion bar pressingly engages the sheet material against the stationary reaction surface of the guide assembly, and, in the inactive position, the abrasion bar permits the sheet material to pass to the tensioning mechanism without engaging the sheet material. When the paper break assembly is in the active position, the tensioning mechanism is operative to pull the folded sheet material across the abrading bar to yield the adhesive bond between the reinforcing fibers of the sheet material. As such, a subsequent cross-fold of the folded sheet material is facilitated.

Problems solved by technology

While these apparatus / systems have successfully served the needs of large volume, mail service providers, several difficulties have persisted, particularly with respect to the efficacy of the fold line produced by the folding apparatus.

Particularly problematic is sheet material which employ “cross-folds” wherein a subsequent fold line crosses over an initial or previously generated fold line, e.g., a subsequent fold line which is orthogonal to the initial cross-fold.

These cross-folds become more difficult to produce when employing relatively stiff and / or thick sheet material such as may be used to fabricate high-quality marketing materials / literature.

That is, due to the stiffness and / or thickness of the sheet material, the cross-fold can produce wrinkles which degrade the aesthetic appearance of the folded sheet material.

Alternatively, the cross-fold can produce a local thickness concentration at the intersection of the fold lines and adversely impact the ability to retain the fold configuration of the sheet material.

With respect to the use of compaction rollers, the nip between the rollers must be highly controlled, and as such, difficulties are encountered when folding sheet collations or sheet material which varies in thickness.

Furthermore, the induced stress concentrations can lead to premature failure of the fold line, i.e., causing the sheet material to tear following a relatively small number of cycles.

Moreover, the scoring apparatus must be highly controlled to avoid cutting through the sheet material and introduces added complexity / cost to the folding apparatus.

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